1. Field of the Invention
This invention pertains to removal of adsorbate materials with an arylene-bridged polysilsesquioxane adsorbent with engineered porosity and to regeneration of the loaded adsorbent.
2. Description of Related Art
The introduction of toxic pollutants can have a severe impact on the many organisms that live in aquatic ecosystems. Phenols, including phenolic compounds, are some of the most common hazardous chemicals introduced by man into such environments. Nitrophenols are introduced by effluent waste from pesticide, explosives and dye industries, and agricultural runoff. Chlorinated phenols are used as decoloring agents in pulp and paper manufacture, as wood preservatives, and are a decomposition product of many herbicides. Of major concern is the stability of these compounds once they enter the environment. Phenols are persistent pollutants that have been found in water, soil, and air samples around the globe, as well as in animal tissues. They have been designated as priority pollutants by the U.S. Environmental Protection Agency.
A variety of techniques have been implemented to purify water contaminated with phenols. Ozonolysis, photolysis, and photocatalytic decomposition have all been used with limited success. The adsorption of phenols into solid supports, such as activated carbons, allows for their removal from water without the addition of chemicals or ultraviolet rediation. Activated carbons have a large adsorption capacity for a variety of organic pollutants but are cost prohibitive due to high initial costs, difficult regeneration, and disposal costs. There is a clear need for a new adsorbent technology for the removal of phenols and other materials from wastewater and the remediation of contaminated sites. For any sorbent to be feasible, it must combine high adsorption capacity and fast adsorption kinetics with inexpensive regeneration. Functional mesoporous molecular sieves may be designed to satisfy all three criteria.
Mesoporous molecular sieves are synthesized using a surfactant template approach that creates large surface areas and internal pore volumes. These characteristics have led to their application as catalytic and adsorbent materials. Although it has been used primarily to synthesize metal oxides, the surfactant template approach is an attractive route for engineering the porosity of a wide variety of new materials.
Lansbarkis U.S. Pat. No. 5,396,020 describes a process for separating hydrocarbons using aryl-bridged polysilsesquioxanes. This 1995 patent describes a chromatographic process to separate at least two classes of hydrocarbons of a solution using an aryl-bridged polysilsesquioxane.
Loy U.S. Pat. No. 5,321,102 describes molecular engineering of porous silica using aryl templates. This 1992 patent describes a process for preparing microporous polysilsesquioxe materials.
An object of this invention is removal of pollutants or adsorbates with a high capacity adsorbent with engineered porosity that is an arylene-bridged polysilsesquioxane or a derivative thereof.
Another object of this invention is removal of phenolic and heterocyclic pollutants with an adsorbent that is an arylene-bridged polysilsesquioxane or a derivative thereof from wastewater.
Another object of this invention is removal or adsorption of more than 90%, on weight basis, of pollutants from gaseous, solid and/or liquid adsorbate materials disposed in gaseous, liquid or on solid carriers quickly in a time period of less than one half hour with an adsorbent that is an arylene-bridged polysilsesquioxane or a derivative thereof.
Another object of this invention is regeneration of the loaded adsorbent that is an arylene-bridged polysilsesquioxane or a derivative thereof by means of a lower alkanol wash or thermal desorption.
Another object of this invention is regeneration of the loaded adsorbent that is an arylene-bridged polysilsesquioxane or a derivative thereof whereby at least about 90%, on weight basis, of at least one pollutant or adsorbate is removed.
These and other objects of the invention can be attained by mixing the adsorbent that is an arylene-bridged polysilsesquioxane or a derivative thereof with a polluted carrier material, removing the adsorbate or the pollutant, separating the loaded adsorbent from the carrier material, and regenerating the loaded adsorbent whereby at least 90% of the pollutant, or a mixture thereof, has been removed.